I would prefer a cryptographer, not Linus, to weigh in on how Linux's PRNG works and what impact RdRand would have on it. It's not that I distrust Linus, it's just that it's hard to separate the vitriol from the facts. That, and a second opinion on the matter would settle it. That'd put the FUD to rest.

However, I found this message a good explanation of what RdRand is/does and how they're integrating it with /dev/random. http://www.spinics.net/lists/linux-crypto/msg05883.html